<Emphasis Type="Italic">TCF7L2</Emphasis>variant genotypes and type 2 diabetes risk in Brazil: significant association,but not a significant tool for risk stratification in the general population

Background  

Genetic polymorphisms of the TCF7L2 gene are strongly associated with large increments in type 2 diabetes risk in different populations worldwide. In this study, we aimed to confirm the effect of the TCF7L2 polymorphism rs7903146 on diabetes risk in a Brazilian population and to assess the use of this genetic marker in improving diabetes risk prediction in the general population.     

CDK9/CYCLIN T1 expression during normal lymphoid differentiation and malignant transformation

CDK9 is a member of the CDC2-like family of kinases. Its cyclin partners are members of the CYCLIN T family (T1, T2a, and T2b) and CYCLIN K. The CDK9/CYCLIN T1 complex is very important in the differentiation programme of several cell types, controlling specific differentiation pathways. Limited data are available regarding the expression of CDK9/CYCLIN T1 in haematopoietic and lymphoid tissues. The aim of this study was to analyse the expression of the CDK9/CYCLIN T1 complex in lymphoid tissue, in order to assess its role in B- and T-cell differentiation and lymphomagenesis. CDK9/CYCLIN T1 expression was found by immunohistochemistry in precursor B and T cells. In peripheral lymphoid tissues, germinal centre cells and scattered B- and T-cell blasts in interfollicular areas expressed CDK9/CYCLIN T1, while mantle cells, plasma cells, and small resting T-lymphocytes displayed no expression of either molecule. CDK9/CYCLIN T1 expression therefore appears to be related to particular stages of lymphoid differentiation/activation. CDK9 and CYCLIN T1 were highly expressed in lymphomas derived from precursor B and T cells, from germinal centre cells, such as follicular lymphomas, and from activated T cells (ie anaplastic large cell lymphomas). Hodgkin and Reed-Sternberg cells of classical Hodgkin's lymphoma also showed strong nuclear staining. Diffuse large B-cell, Burkitt's lymphomas, and peripheral T-cell lymphomas, among T-cell lymphoproliferative disorders, showed a wide range of values. No expression of CDK9 or CYCLIN T1 was detected in mantle cell and marginal zone lymphomas. However, at the mRNA level, an imbalance in the CDK9/CYCLIN T1 ratio was found in follicular lymphoma and diffuse large B-cell lymphomas with germinal centre phenotype, and in the cell lines of classical Hodgkin's lymphomas, Burkitt's lymphomas, and anaplastic large cell lymphoma, in comparison with reactive lymph nodes. These results suggest that the CDK9/CYCLIN T1 complex may affect the activation and differentiation programme of lymphoid cells. The molecular mechanism through which the CDK9/CYCLIN T1 complex is altered in malignant transformation needs to be elucidated.     

Use of specific ELISA for the detection of antibodies directed against p53 protein in patients with hepatocellular carcinoma.

AIMS: To analyse the significance of antibodies to p53 protein as a serological marker for changes in p53 gene expression in patients with hepatocellular carcinoma. METHODS: Thirty eight patients with hepatocellular carcinoma, 19 showing accumulation of p53 protein by immunohistochemistry and 19 having no accumulation, were studied. The presence of anti-p53 was tested using a novel ELISA utilising a recombinant p53 protein as a capture system and verified by western blotting. p53 gene mutations were sought by single strand conformational polymorphism and DNA sequencing analyses. RESULTS: Of 19 patients with p53 protein accumulation in tumour tissue, 10 (52%) had antibodies to p53 in serum by ELISA. Four patients with p53 negative immunohistochemistry also had detectable anti-p53. Western blot analysis confirmed the specificity of the ELISA positive serum samples. The presence of anti-p53 was independent of serum alpha-fetoprotein and was detected in 50% of small tumours while only 8% were alpha-fetoprotein positive. Mutations affecting exons 5 and 6 seem to be more frequently associated with development of anti-p53, than mutations in exons 7 or 8. CONCLUSIONS: The ELISA for anti-p53 is a convenient and specific tet for the detection of humoral response to alterations in p53 gene expression and could be of value in the diagnosis and characterisation of patients with hepatocellular carcinoma.     

A novel glycoprotein for detection of herpes simplex virus type 1-specific antibodies

A novel herpes simplex virus type 1 (HSV-1)-specific glycoprotein reactive with monoclonal antibody H1379 was purified by affinity chromatography. This glycoprotein, provisionally designated as gG-1, forms two sets of bands with molecular weights of 40-44,000 and 60-88,000. When used in an immunodot enzymatic assay, gG-1 reacted strongly with rabbit antisera to HSV-1, but not with sera hyperimmune to HSV-2. Specificity of the assay was further established by the lack of reactivity of convalescent sera collected from 20 patients with primary genital HSV-2 infections, and from 100 sero-negative individuals. In contrast, antibodies to gG-1 were detected in 9 of 10 patients with primary HSV-1 infection, and in 63/67 patients with culture-positive, recurrent oral or genital HSV-1 infection. Reproducibility of the gG-1 immunodot assay for HSV-1 antibody detection was 96%. Serological assay with purified gG-1, done in parallel with the assay using purified gG-2 described in an earlier report, provides simple and reliable methods to detect type-specific HSV-1 and HSV-2 antibodies for seroepidemiological studies.     

In situ immunogold labeling analysis of the rice hoja blanca virus nucleoprotein and major noncapsid protein.

Ribonucleoprotein particles (RNPs) of rice hoja blanca virus (RHBV) were purified and used for electron microscopic analysis and antibody production. Antibodies made to RNPs specifically decorated purified RNPs. The RNPs typically showed characteristic tenuivirus morphologies. They were approximately 8 nm in diameter, mostly circular in nature, and exhibited branching and a high degree of superhelicity. When the RNP antibodies were used for in situ immunogold labeling analysis of RHBV-infected tissues, no specific structures were identified, but gold particles were distributed throughout the cytosol of RHBV-infected but not healthy plants. However, amorphous semi-electron opaque inclusion bodies (ASO-IBs) were abundant in cells of RHBV-infected plants. While the ASO-IBs were not labeled with the anti-RNP antiserum, they were specifically labeled with antibodies to the RHBV major noncapsid protein (NCP) and with antibodies to the NCP of another tenuivirus, maize stripe virus.     

5-Azacytidine produces differential undercondensation of alpha,beta and classical human satellite DNAs

Fluorescencein situ hybridization employing human alphoid, beta and classical satellite DNA probes was performed on 5-azacytidine treated and untreated chromosomes obtained from human lymphocytes. The individual used in this study presented a polymorphism of constitutive heterochromatin of chromosomes 1 and 9 as revealed byin situ digestion with the restriction endonucleaseAlul. Neither the alphoid nor the beta satellite DNA domains were susceptible to condensation-inhibition by 5-azacytidine. Only the classical satellite localized on chromosome 9 was affected. The constitutive heterochromatin size polymorphism was shown to depend mainly on variations of the classical satellite DNA domain. Therefore, condensation-inhibition, as a phenomenon which may modify the natural folding of the chromatin fibre, regionally affects human constitutive heterochromatin and seems to be dependent on the heterochromatic family.     

Adenoviruses in faeces of children with acute gastroenteritis in Rio de Janeiro, Brazil

Faeces from 746 children less than 5 years old with acute gastroenteritis were screened for the presence of adenovirus particles or antigens by immunoelectron microscopy (IEM) and enzyme immunoassay (EIA). Thirty-five samples were positive by both IEM and EIA, two only by IEM, and two only by EIA, giving a total of 39 (5.2%) samples with positive results. Of these, 25 could be propagated in HEp2 cells and were neutralized by one of the antisera to adenovirus types 1 to 18. The remaining 14 samples could be propagated only in the 293 permanent line of human cells transformed by adenovirus type 5 DNA [Graham et al, 1977] and were not neutralized by antisera to adenovirus types 1 to 31. An EIA carried out by the antibody-capture technique, using antiserum specific for "enteric" adenoviruses [Johansson et al, 1979], gave positive results with all isolates that could be propagated only in 293 cells and with none of those capable of growing in HEp2 cells.     

Some endocrine and morphological aspects of the acute toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

Hormonal status was evaluated in TCDD-treated rats and in pair-fed and ad libitum-fed controls in order to separate hormonal changes resulting from the toxic insult of TCDD from those arising from progressive feed deprivation as it occurs in pair-fed controls. TCDD-treated rats received either a usually non-lethal (25 micrograms/kg) or a usually lethal (125 micrograms/kg) dose of TCDD whereas pair-fed and ad libitum-fed controls were given vehicle alone. Animals were terminated at predetermined time intervals and several hormones measured in serum or plasma. In addition, the morphology of the thyroid, pancreas, and pituitary was also examined. In both dosage groups, TCDD-treatment had the following effects: decreased TT4, FT4, insulin, and glucagon; mixed effects upon TT3, FT3, TSH, and GH. Pair-feeding to the non-lethal dose of TCDD had no effect on any of the hormones measured. Pair-feeding to the lethal dose of TCDD had the the following effects: slightly decreased TT4, FT4, TT3, TSH, and insulin; no effect on FT3 and glucagon. It is concluded that the endocrine status of TCDD-treated rats was different from that of pair-fed rats suggesting that some hormonal changes represent responses to an insult other than that due to starvation stress alone. A differential response between TCDD-treated and pair-fed rats was also observable morphologically in the corresponding endocrine glands indicating the importance of this additional control for morphologic observations in instances when reduced feed intake and body weight loss are prominent features of toxicity.